This theory is 100% written by me. In no way is this copied or even changed from another person's theory, despite what you may find elsewhere. There have been other websites that have copied my theory without giving me credit. Now I am not conceited, it is very possible for another person to think of the same theory I have, but when others have it recorded the exact same way I do for the exact same reasons, one begins to wonder. But rest assured, I take pride in my theory and I enjoy doing it and sharing it with the Zelda community. So please, if you want to use it, I am really not going to care if you do, as long as I get credit and I know about it. That is all I ask.

There are some events that may be considered spoilers. Turn back now if you do not want a thing ruined.

First Tetra means four. And at one point, before it was the Triforce, it could have been called the Tetraforce. Tetraforce meaning that it was once a solid triangle made up of four pieces. For the sake of this theory, the Tetraforce will only be called that when I talk about the complete triangle. Otherwise, each piece will still be called the Triforce (i.e. Triforce of Power, not Tetraforce of Power).

This entire theory started when Ocarina of Time was released. When you received the Hylian Shield in the game people began to wonder. They wondered what on earth is the upside down triangle on the shield. Is it the missing middle piece of the Triforce? And if it is, then who is to govern over it?
What threw it off even more, is Ocarina of Time explains the three goddesses and the beginning of Hyrule, and their part in the creation of said land. However, as you progress through the game, there are subtle clues laid about. One of them is one thing that Saria says to you when you play her song.
I think it is kind of funny to that right after Navi asks, “Do you have any idea what he may have meant by this?” First, it is a typo, it is supposed to say she, but another reason why it is ironic is because it doesn’t make sense. Sure the Desert Goddess could just be someone the Gerudos look up to, a beautiful person, but this also can be taken that there is yet another Goddess in the mix. One perhaps forgotten about.

The next clue that was given out was within Majora’s Mask. After you receive the Ocarina of Time, Link has a flashback where Zelda specifically says, “…The Goddess of Time is watching over you.” Wait a minute. Din, Nayru, and Farore are the Goddesses of Power, Wisdom, and Courage, respectively. So now we have a possible goddess, a facet she governs over and a missing Triforce piece.

Another reason that this is so important it because of the connections it makes. If the quote from above speaks of a Desert Goddess, and the final Triforce piece is in fact the facet of time, it makes sense that the Spirit Temple needs to be defeated only by traveling through time between child and adult.

There have been symbols, designs on people’s clothes, things hanging from walls, even directly chiseled into the wall of the Spirit Temple. These pictures are of eyes, staring deeply, maybe signifying that there is more that meets the eye. Anytime you see the eye, it has something to do with time. There is a room in the spirit temple where a poster, of what looks a lot like Vaati (explained later), is on the wall with an eye. Also, the Gossip Stones have the eye on them, what do they do when you hit them? They tell you the time. The Mask of Truth has the eye on it. This mask allowed you to see things you are not normally able to see. This suggests that the Goddess of Time can talk directly to people’s minds, thus talk telepathically. When wearing the Mask of Truth, the Gossip Stone’s quote: “It’s one eyed gaze pierces into your mind.” So using the mask you can talk telepathically. In addition to that, when you hit a Gossip Stone, what does it do? It tells you the current in game time.

Now after these clues were gathered I continued to look elsewhere for more clues. I started back at the beginning of the franchise where yet again upside down triangles appeared.
This is the art of Link from A Link to the Past, and on the shield are two upside triangles. Well, what could this mean? Maybe at one point the Triforce of Time was split into two pieces. The Triforce of Time would be a very powerful piece all in its own, so maybe the Goddess of Time split it up into pieces to protect it and scattered them throughout Hyrule. So I continued to look into more connections of two pieces, bringing me to the over world of A Link to the Past.
On this picture, you can spot the two triangles in the design of both over worlds.

In addition to this, in The Legend of Zelda, Ocarina of Time, go to the lone skull kid as child or adult (if you go there as adult, kill the lone skull kid and collect 200 Rupees and get him out of your way). After that, look up into the sky. There are two beams of light coming down from the sky, but the shapes of the beams of light are two triangles. Kind of strange?

Now you may be asking, what is the purpose of two pieces? Like I said above. The Triforce of Time would be a very powerful piece all in its own. But what would happen if one obtained it. Now this is pure speculation but I believe at one point Link was once evil. What leads me to this conclusion is when you receive the Fierce Deity’s Mask in Majora’s Mask. First, when you click on it the item description says that you can use it’s dark powers. Dark, usually symbolizing a form of evil. However, what tipped it off for me is the fact that the mask looks like an adult form of adult Link. Now why does the mask look like Link at all when he never was a deity in the first place. First off, deity means god, a form of higher power. Then I inspected the Fierce Deity even more and came across a startling discovery.
First, on his chest he has a complete triangle. Perhaps the Triforce was complete at one point. And one man obtained all four pieces, turning him into a deity. Another thing that I found interesting is the sword. It is called a double helix, meaning it goes on forever, kinda like a sideways number 8. This would make even more sense that the wielder of all four pieces would live forever, having time, power, courage, and wisdom on your side is seriously advantageous. Perhaps at one point, Link was alive and obtained all the pieces, then the goddesses saw this as powerful and stripped him of it after an intense fight. The Tetra force (the complete triangle on his chest) was then split into four pieces, and then the Triforce of Time was then split into two pieces to keep it from anyone obtaining it again. At this point, the Tetraforce became known as the Triforce, and the remaining 3 pieces were kept in the Golden Land. Link’s dark spirit was then sealed inside the mask, making it look like him. The goddesses then decided, as a penalty for his deeds, he would then be reborn every 100 years as punishment. A side note: Maybe this is where Shadow Link spawned from, a leak in the mask (this is for another time).

The reason I think Link was once evil is because of the thing the kids say on the moon in Majora’s Mask. For being kids, these are very deep things to be said. Perhaps even more clues to a possible existence before this point.

Odolwa kid-
”Your friends... What kind of... people are they? I wonder... Do these People... think of you... as a friend?”

Goht kid-
”You... What makes you... happy? I wonder... What makes you happy... Does it make... others happy, too?”

Gyorg kid-
”The Right thing... What is it? I wonder... If you do the right thing... Does it make... everybody happy?”

Twinmold kid-
”Your true face... What kind of... face is it? I wonder... The face under the mask... Is that... your true face?”

Majora kid-
”Will you play with me?
(yes)
You don’t have any masks left. Well lets do something else. Lets play good guys against bad guys... Yes. Lets play that. Are you ready?” (he hands Link the Fierce Deity’s Mask) “You are the bad guy. And when you are the bad guy, you just run. That’s fine right? Well... Shall We Play...”

It says it right there again. “You are the bad guy.” Interesting? In addition to this there are four kids; four pieces of the Tetraforce.

Now every Triforce piece has a color. Triforce of Power is red, Triforce of Wisdom is blue, and the Triforce of Courage is green. You are probably asking, “If the Triforce of Time is real, than what color is it?” Well, that is a great question. You see the Triforce of Time has to be purple. Any time that Tetraforce clues were given out, purple was nearby. For Example: In Zelda II The Adventure of Link, the sixth castle was purple. And, also when you used the whistle to make the castle appear, it appeared in the middle of the three other rocks that happened to also be shaped in a triangle formation. Also in The Legend of Zelda: Four Swords, if you play four players, the final tunic color was purple. Makes sense seeing that Vaati has an eye (symbolism) and the games that he appears in you control four Links at some point.
If the color thing is correct, then the Master Sword’s hilt being purple would make sense since it allows you to travel between times.

The Wind Waker even has clues strewn about. When you place all the crystals in their pedestals to make the Tower of the Gods rise, the three orbs fire an energy beam at each other creating a Triforce in the middle of the ocean. The Tower of the Gods rises in the middle of the Triforce and what does it house? The Master Sword.
Also the crystals have the same design as the songs in Oracle of Ages for the Harp of Ages, which (of course) allows you to travel through time. Also, Tetra turns out to be Zelda, which she told you in Majora’s Mask (not the same Zelda, but her bloodline does wield the Triforce of Wisdom) about the fourth goddess in the first place. A side note: maybe Zelda is the fourth goddess, she is reborn every 100 years along Link, why (this is for another time)?

The final thing to address is the legend itself. Many will scoff at the Tetraforce mostly because in every game it is called The Triforce. That may be true, but it is called the Triforce because that is how it is being told to us. To Hylians, it has always been a Triforce. That is what their legends say. But that doesn’t mean that at one point there was a fourth, and the goddesses didn’t want the people of Hyrule to know about it, so they changed the legend itself, turning this into what it is…a theory.

NOTE: With the launch of Skyward Sword in 2011 is has been verified that Zelda is in fact the fourth Goddess known as Hylia. This theory at the moment will not be re-written to reflect this as Zelda being proven to be a Goddess and a fourth one at that only helps this theory out.

With the launch of Tri Force Heroes in 2015 it has been verified that Fierce Deity was in fact evil at one point.